bernard



A. A. BERNARD ROLL CRUSHER FOR SUCH METALS AS ALUMINUM Feb. 7, 1956 2,733,866

AND ZIRCONIUM WITH MEANS To REDUCE THE STATIC CHARGES 1N THE cRUsHER OUTPUT 4 Sheets- Sheet l Filed March 18, 1953 @Az/M @5553@ BY i M,M,MZ

Feb- 7, 1956 A. A. BERNARD 2,733,866

ROLL CRUSHER FOR SUCH METALS AS ALUMINUM AND ZIRCONIUM, WITH MEANS TO REDUCE THE STATIC CHARGES IN THE CRUSHER OUTPUT Filed March 18, 1955 4 Sheets-Sheet 2 r 5 f u?, u T6 0 w R i 4, Q n WWW# r/////H/ ////,//////////////////////fM/%4wwww/ //////v/,/ ////////////////////////M// m//// a. 1 m l? L. M

Feb. 7, 1956 A. A.

ROLL CRUSHER FOR AND ZI O M,

STA Filed March 18, 1953 BERNA RD 2,733,866

SUCHV METALS AS ALUMINUM ITH MEANS T IN THE CRUS EDUCE THE INVENTOR.

@if/@Ma mm/Wm,wuwik9w Feb. 7, 1956 A. A. BERNARD 2,733,866

ROLL CRUSHER FOR SUCH METALS As ALUMINUM ANO ZIRCONIUM, WITH MEANS TO REDUCE THE sTATIC CHARGES IN THE CRUSHER OUTPUT Filed March 18, 1953 4 Sheets-Sheet 4 NHL..

` fan-ne ROLL c-RUsHER non sucHiv1ETALs--As ALUMi- Arthur-alumna chicago, In., assigner to National 'C'ylind'ri GasvCompaliy,v Chicago, LIll,A a 'corporationdof This. titration; relatas'senerally. ma Crushing arpa- States Patent O inthe crusher. The crushing of the small particles below ratusls we as -an improved l process of crushing granular v latefil i111.11 51119?? Partiularly' 19. an .impaired devise.' fr" miing granular ma'ferial'tol particles ofV predeterminedk 'ae 16191K. prt1d11ing1St11t shares? 0111111e `vThe apparatus ofthe present inventionis` particularly adaptable-.fat pmduins @maimed Pattislefta be wir 1f t9 15a iclafadias Systems which are. rsquifd t0 he presentY apparatus" 'isi` useful-'in'l providing ng systernsjo'fthe typef'disclose'd iny co4 lar material lforuse with` accurate feeding devices is to thenparticlesfto' the desired size. lIn"mostjcase's,

.j commercial supply"':hroiisesV andl arey ordered theref frein in j 'Balk' fanti-1T The 111111.# i 111ff\1e11"a.1 Contains" an. app ciablepercentage ,of small particleswhiclihave been in size by vibration,` handling of the bullcrriatfe-4 reduc ria'lg-falndyothersirnilar operationsdwhich occur in transit. Generallyg theprior systems for,l vreducing the size `of` the particles of. the'bulk material have involved ballmill or hammer mill type pulverizingequipmentl to which'lthe. bulk materialis fed. The grinding hammers o r crushing ballsof the prior. apparatus'reduce the size of` allof the particles in` the bulle Amateriali including` the particles whieh "arey smell) enough orv too small, by repeated blows appiied-to tiielmateriai vfed to iheequipmenf. tris' theeffore thatl'the ball"v and hammer crushers" act uponthe smaller particles `of the bulk material which have already Ibeen reduced t'othe' desired size, whereby the si'z'e oifthese particlesl is reduced beyond that which is desired.lv The constant pounding of the granular material f reducesa portion of this material `to dust or powder compris'ing n'iinute particles and', for many purposes,l thel 'actir a taassribsd fquafities O'f matrl- More,

L c -r 1 1 1 t .Y 1; 2,1. 011111111 511111111111111 0.1 other sampound for,

riesig` ap icattenfs.; ser 1f =Nes. 343,097 "and y 343,098; 1

les are, several v tittiesv larger than those inthe feeding apparatus in order to permit reducfl rticlesnwhichlare't' be crushed are obtained are 'crushed andrrefduced to a size :which closely approxi-A mates the spacing between the rollers. The`"gra1 ular particlesin the output of the crusher are therefprelm'a" tained at a uniform size and, byadjusting' the sjggacing'lbreiy` tween the', rollers, this size mayf bevaried to`tlitaimpar-n ticles ofy any desired size." vThe passag'eofth particles directly through the crushing apparatus reduees 'by'anappreciable extent the lamount of material "subjected to frictional'contact and thes'tatic charges induced in the output'of the crusher are thereby minimized. The

presence-orthse Tminute particles in the output oflvthe crusher is'ihighly undesirable. For this reason, the"4 detritus output Tofv the prior art'` Crushers has consisted of particles which are not `uniform in size and which containA al considerable quantity of triturated particles.

further disadvantage of these priorsystems has been the Vintroduction of; 1 electrostatic charges to v the comminuted .particles by the` lexcessive friction induced by repeated pounding andfbeating'` of the bulkfmaterial. The amount of static charge induced `is 'directly` determined by the frictional forces to which the material is subjected n 2,733,866 Patented Feb. 7, 1956 ICC the size which is actually desired resultsin the application of irictional Aforces to these particles thereby creating an unnecessary source of static charges. VThe granulated particlesappearing inthe outputV of the prior systems are therefore electrostatically charged so that when these" particles are supplied to a feeding system, the particles tend to'clingutogether and adhere to the walls of the' feeding apparatus. Under these conditions itis virtuallyY impossible to feed accurate measured quantities ofthe material through the feeding mechanism.

The present invention obviates these diliculties by providing a crushing apparatus which includes a plurality` olf` aligned crushing rollers cooperating in `pairs to comminute material which passes therebetween. The pairediroll'ers' are spaced'a'small distance apart so that those particles" of the bulk material which are smallerthan the space `be tween the rollers pass directly through the'crusher rwithj` out comminution. Thus, the smaller particlesare not reduced size andthedetritus output ofthe crushingq apparatuwsecontains a minimum of dust and powderedf; material. lAll particles of the bulk material"whichjarel larger thanone of the, spacesI between the: pairedfroll'ei's`V crushing of material between the rollersfavoids the necesi` sity of r'epeatedpounding and reduces the frictional contactV thereby, greatly reducing the static charges produced` in the crusher output. As `soon as thebulk material is reduced to a size which allows the particlesto 'passf'be-,-

tween thesmallest spacelbetween the rollers, the particles pass directly through the crusher without further frictional vContact with the crushing mechanism.` In this4 manner-,contact between the particles and the apparatus is maintained at a minimum and the granular output ,of the crusher is free of charged particles so that the output to deliver. accurate quantities of materia1.`

is suitable for use with r feeding systems which are required Accordingly, it is an object of the present invention'A to provide a crushing apparatus for producing particles of uniform size.

It is another, object of the present invention to provide i a crushing apparatus which reduces granular material)` to particles of predetermined size which are relatively free of dust and other powdered material.

A further object is 'to provide a crushing apparatus which reduces the sizeof particles with a minimum of frictional contact so that the output of the crusher is.

relatively free vof electrostatically'charged particles.

A still further object is to provide a crushing device in which particles smaller in size than those which are desired are passed directly through the crusher without i comminution.

A still further object of the presentinvention resides in an improved process of reducing the sizeof granular material without subjecting the resultant product to undesirable electrostatic charges during the crushing op-A eration. i

-Another object of the invention is to provide a crush-1 ing machine employing spaced rollers in which the spaces between the rollers permit particles below a predetermined size to` pass through the rollers without `comminution and-in which palticles larger than thev spaces between the rollers are crushed so that uniform sized particles, free of static charge, are emitted from the crusher.

Further objects and advantages of the present invention will become apparent as the following description proceeds, and the features of novelty which characterize the invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

For a better understanding of the present invention reference may be had to the accompanying drawings in which:

Fig. 1 is a front' elevational view of the crusher of the present invention having a portion of the front panel broken away to show the details of the driving connection for a crushing apparatus which is characterized by the features of the present invention;

Fig. 2 is a partial sectional View taken substantially on line 2 2 of Fig. l assuming that Fig. l shows the complete structure in order to show the details of the crushing mechanism;

Fig. 3 is a sectional view of the crushing mechanism taken along a line substantially corresponding to line 3,-3 of Fig. 2, assuming that the entire crusher had been shown in Fig. 2;

Fig. 4 is a rear elevational view of the crusher of Fig. l having a portion of the rear panel broken away to show the details of the driving connection and the mountings for the Crushers; l

,Fig. 5 is an enlarged sectional view taken along a line substantially corresponding toline 5-5 of Fig. 3, assuming Fig. 3 shows the complete structure, to show the feeding slot in the crusher;

, Fig. 6 is a sectional view taken on line 6--6 of Fig. 5 and again assuming that the entire crusher had been shown in Fig. 5;

Fig. 7 is a sectional view taken along line 7--7 of Fig. 6, assuming Fig. 6 lshows the complete structure, to show the details of a portion of the feeding mechanism which controls the ilow of material to the crusher;

Fig. 8 is an enlarged broken-away portion of the apparatus of Fig. 4 showing the details of the mountings for the Crushers;

Fig. 9 is a partial view similar to Fig. 4 but reduced'in size illustrating a modiiication of the present invention; Fig. 10 is an enlarged view of a portion of Fig. 9;

Fig. 11 is a sectional view taken on line 11-11 of Fig. 10, assuming that Fig. 10 shows the complete structure including a rwall portion which was cut away in Fig. 9; and

Fig. 12 is a sectional view taken on line 12-12 of Fig. l0, again assuming that Fig. l0 shows the complete structure.

Referring now to the drawings, wherein like reference characters designate like or corresponding parts through out the several views, there is shown in Fig. 1 a crushing apparatus indicated generally as including a housing having a horizontal base 21 and a pair of parallel vertical front and rear panels 22 and 23, respectively, secured to the base in any suitable manner. The housing of the crusher is divided into upper and lower sections 24 and 25, respectively, by a wall 26 which is supported between the vertical front and rear panels and which is provided with a comminuted material delivery passageway 27 and a drive connection opening 27a, the purposes of which will become fully evident as the description proceeds.

The lower housing is divided into a detritus receiving chamber 28, which is positioned below the material delivery passageway 27 so as to receive the output of a crusher mechanism indicated generally as 29, and a motor housing compartment 30, which encloses a driving source 31 for the crusher mechanism. A drive connection indicated generally as 32 interconnects the driving source and the crushing mechanism to supply power to the crusher. Particles of material are fed to the crusher from a granular material storing hopper 34 by a flow regulating feed mechanism 33 which supplies material grasses j .4f l Y to be comminuted in a manner to be subsequently described in more detail.

In order tov provide an enclosed lower housing,l the lower section 25 of the crusher includes parallel side panels 35 and 36 which interconnect the parallel front and rear panels and are secured tothe base 21 and to the separating floor or wall 26. The enclosed lower housing thus' formed may be divided by a transverse vertical compartmenting plate-37 into rthe detritus receiving chamber 28 and the motor housing compartment 30. To permit access to the detritus receiving chamber, the side panel 36 may be provided with an access door 28a hinged on the side panel in'any suitable manner. The access door facilitates the removal of the comminuted output of the crushing mechanism 29which is deposited in the detritus receiving chamber. The driving source 31,which may be of any suitable type, is shown in Figs. 1 and 2 as an electric motor which is supported in a position adjacent to the upper housing by a motor supporting floor 38 extending parallel to the base floor 21 within the motor housing compartment 30. The positioning vof the driving source near .the upper housing and near the crushing mechanism 29 avoids the necessity for extended driving connections between the upper and lower housings and, hence, simplifies the mechanical structure of the drive connection 32.

The upper housing 24 includes a vertical side wall 39 which is secured to the separating lloor 26 and extends upwardly to form one side of an enclosed crushing chamber 40 for the crushing mechanism. Also secured to the separating iloor and extending upwardly are a pair of parallel chamber-forming plates 41 and 42 which are positioned perpendicular to the side wall 39 so that a cornpartmenting wall 43a which joins the chamberfforming platesl completes a rectangularenclosure to form the crushing chamber 40 in the upper housing. The parallel plates 41 and 42 extend upwardly beyond the crushing chamber 40 in order to form two sides of the hopper 34 and are provided with a plurality of shaft positioning apertures 41a for purposes which will subsequently appear evident. The front panel 22 cooperates with the parallelplate 41 and the side wall 39 to form a gear train housing 43 for encasing a driving gear train mechanism indicated generallyas 44. The gear train housing serves to protect the moving parts enclosed therein from dirt and moisture, and in addition serves to protect the clothing and limbs of the crushing machine operator from entanglement with the gear train. For protection against similar hazards, the rear panel 23 cooperates with the parallel plate 42 and the side wall 39 to form an enclosed driving assembly housing 4S which extends the entire width of the parallel plate 42 and encases a portion of the driving connection 32 between the driving source 31 and the crushing mechanism.

As was indicated above, the hopper 34 is positioned above the crushing chamber 40 by the parallel plates 41 and 42 which constitute two sides of the hopper, the other two sides of which are formed by the side plate 39 and by a hopper-forming partition 46 extending between the parallel plates. The hopper may be provided with a pair of converging bottom sections 47 which form a trough for feeding the granular material fromthe hopmechanism 33 is positioned below the elongated opening 48 in the hopper. This mechanism includes a. ma terial retaining leaf 51 and a slotted material feeding plate 52 which are contiguous with' the guiding members endv 55,1 which; may be of `felt or; other nonf abrasive material, inr contatwith a material distributing feed roller 54. The slotted material feedingnplate is positioned closely adjacent the feeding roller 54l near the openingAS inI the` hopper so that material whichdropsA frojxr x.theh opper onto,` the feed roller passesthrough, a plnrality of `slots 52a formed in the .bottom of .the plate SZQasbeSt-shown in Fig., 7... By varying the. number agld-sizef-oftheslotsfin thematerial :feeding plate,.thev regel-.oe `:flow of.Y material; tothe .crushing mechanisml `29 For;-the. purpose of supporting the feed `roller 54xthe i lattergismounfed `on a rotatable feed rollershaft'. 55

whichf'extendsbetween the,l side plates 41 and 42- and 'fits withinvonei of the shaft receiving apertures 41my in each l ofzfsaid side plates.. Secured to each ofthe siderplates incorder to .journal 'fthevends of :the feed roller shaftV 55 which extend through the shaftv receiving apertures are-a pain ofifeedfrollenbearing assemblies 565 A feed roller gear 57 which is one element of the gear train 44 vis mounted on* the feed roller shaft 55 in order to themovement of the gear train to the feed roller.`

v VVertcally aligned with thefeed roller 54are a plu- `ralitynoffrotatableV crushingrollers 58a, 5812 Zandt 58e, theiaxisof-each of which is fixed and which faxes 1are` spaed from one another. The crushingrollers "are niount'ediion crushing roller shafts 59a, VSi9b`and 5 9cL4'1 respectively,` which are vertically aligned `with theffeed--` roller -shlaftS'S and which Vextend through the shaft` receiving apertures inthe parallelV plates lwlfancli 42;; l"The bly. .and inw. the.. saar 'trainlhcusins `43 are-.debated th feedroller gear 57 .andv are/operably interconnec du; Wi, fssdrollsrsear-by pnionjgears 66a, 6.6.11. @466C wh are secured to pinion gear shafts. 6'7` rotatably,

ated. f Within Shaft .positioning 'apertures` in; the steel y ed,y roller andrithe j, crushing rollers.v

thehcrushingvcharnber at).A in; a position n twhich th e.. `ad justably rnounted rollers are horizontallyalignediwith thevixed rollercrushers 58a, 5811 and 58e, respectively..`

respectively, mounted on roller erushervfshafts 79a," 7`9b and 794e,V eachof which. is rotatably journalledwithin adi pla s'lzllt anidglit..` The. bearing assemblies `861 are sec'ur d tothe parallelvlplatves by detachable retaining bolts 811;..whic`h maybe .loosened to permit the adjustable rollers tobegnjiovedttowardgor awayl from the fixed rollers for. `jnfll'ploseslwhiclibwilljhereinafter be clearly` eirtialained.i i

` to.v interconnect ,s the. adjustablev rollercrushers. g r. trairlyigllflllthe shafts 79a 5'9b|` and 79gl ',re

P ded; with. follfrf Crusher', ses `8.241,1 .82@ and? Sie.' l 11Y,Yl1.1.itlln,1el1 with the roller. washer. sears; 65a, 65b and 65e, respectively, within the gear train impart l M41.; The.` pinion gear `66a'. simultan,o'uslyV rneshesl, wir lifefeedroller gear. 57 .andthe @per 'Crushisollsr whereas each .oflthewlothertwo ,pinion gears .665. and'` simultaneously@ meshes vwith twoY rof thel 'erusljing'` gears; thereby Vcompleting .the` irkiterconnection.1 of.;

.Apluraliftyof adjustably. `mounted `rotatable,` Crushers.: 76,41, 76ban.d 7`6qiare vertically aligned and, spaced within;

Theb adjustable. rollercrushers 76a, 76b-V and 76e Aare] ble bearingfassernbliestl secured `to the parallel f 60' to set the rollerspe'riodically to` .tee'th on themeshingcrusher'fol i Y l ment Yofr the adjustable rolleiftowrdsmthefiired rollet'f l. :th-5 i 1 .r-.axissofroneOffeachepaira is .fxedly mo ntelgbetweemthel. arallel,plates-,and.-the-e axis of tlregother1 is movable. toward-or away,rfro.1n ,tl 1 e.. tiredlyA mounted roller, axis.` lnaccordance.. withathe. present invention, thefxed rollergoeach pair isspaceds a.` srnall distance from t .the .adjustableV roller.v sothat .ma-L terial- -whicln is fed fthereto, from.; the: ilow..y regulatingti mechanism 33 L mayV pass.. between.. theta. rollers. to.be';v UJll- Preferablythespacingbetweenthe supper, pair. of rollers 58a .anl76avis .larger Jthan. the spacing betweenli th; 0111er pairseand the spacingbetween` eachsuccessive,` painof rollers ybecomes decr'easinglyi smaller. .,Thatis;u the spacing between. thei ro1lers"58az`aud V76:11slargei` than the spacing between rollers` 58bt and 76b which, inl turn, is larger-than thespacin'g betwe'entroller's` 58cand- 76C. Although three pairs of-rollers Yare illustrated yina the drawings,iit` is obvious that any nunberof pairsiixnay be utilized depending upongthe type ofrmaterilal tovbe" crushed and the size oflparticlestdesired y i l't 4now'becomes apparhtthatas the materialis fed to the. first pairtof crushingirollers 5 8qland 76q1froni theu ow. regulatingniechanisin 33,`a1l particles of the 'maf terial which are'smaller than th'eTspaCingbetWee the" rollers fall.directly=-through theispa'cing vvitlroutbeing4v crushed; whereas alliparticles'largerA than the 'Sla'liign are crushed by .thesreratiggrbf rhetouers. "fantasmi which pass withoutfconjrninutign through the sparsi between "the r'stfrollers'aindtli 'particles which 'are :co niinuted by tltei'rst rollershowsu'ccessively to.thehotli pairs of rollers 5817K'-andjb'ifandfSSandw76cff` particles v'in the hopper which are snaller than tliesrnV estispacng; betweeri any of- 'thef rollerv will 'pa through alloi thev'rollr's without com `l manner allp'articles inI the hopperfy wh .s been reduced;l to Vs'rn'all fsize. by h; ndl transp() tion leffects )flow directly through the c rus h er and are reduced to powder "or dust.l i'iotheriniportant'elfeet i passing the srnall` particles"ftllroii'gli'h the; ruslier. conirnir'lution'is "that 'tlielistatic charges induced byfff tional "Contact vbetween the'i .V i i' l' i n reduced to a 'rniriiinurnl` The pr enceof`ch`ar""d ticles in the ouetput`fofftllem`crumaterial fvery diiiieult to haY in wilma-they. are ssbsegaehnyplced .fsf .distribue -Thetspacing between geaclifpainc'tfgrclillers "liey justed bylloo'snin'g the reta1 hgboltsuSI-ar'iii vrricivin the bearing asseniljlies'slll A tli "f i A i moved,` the bolts'"81 `slide within the parallel plates. thereby inoviilg t shaf'tfwithin'tlle slots 'Sll Vu ritil ytheV by thedesired spacing', VTh reta be tightened to"lo,`.cl "thge bei" adjustable roller` in the fd crushing of `n'on-fr'iablematerial ing of the roller surfaces4 s'o`t s' bolts.. S1 mayihei.. asemblyl 89 andthe' i i weer. Regata.' ltsiri "a .ardilaljw ,r 1 itl beconiesvnecssary a @required .Spacinsm order to"coinpen`sate for the wear. Wear ,on the roller". surfaces may ybeA :corrected I'by sirr'rplj adjusting the rif ing. assembly'. 805m se mainefhefeifor@ lease EventuallyLafter repeated `adj vthe lengthwof t1 Ier gears. liinits the'rno When the gear teeth lirnit thefroyetnent offthe: adjustable roller, sirnplyadjustinentof the roll Vitio'rlilriof lo l corrects 'for 'the erosin of theA surface and it becomes.. necessary to replace the rollers." i n Fromv the foregoing descriptioni't is obviuis that iffit. isdesirfedxo crushtaffriable na'terial, only onefont-'wvo pairsv oflcrushing frolleis, may. be. requiredY an'd the s'pac; irlgbetween therollersimayl bervery,` smlhf AQrrtlie oth'env hand, if nonzfliableparticles arei'tobefcmminutedg, sev.'

eral pairs of crushers are preferably used in which the araches,

spacings between the pairs are reduced very gradually.

In order to remove any particles whichtcndto adhere tothe surface of the rollers, the feeding roller and each of the crushing rollers is preferably provided with a particle removing wiper blade as shown in Fig. 3. The

wiper blade for the feeding roller is` designated 83' 84 and the parallel p1ates'41 and 42. The wiper blades 82a and 82b free the rollers of material which clings to the surface and direct the freed materialfto the next succeeding pair of rollers. The wiper blades 82e for the rollers 58e and 76C direct the freed particles through the comminuted material delivery passageway 27 and into the detritus receiving chamber 28.

The driving connection 32 'includes the sprocketwheel 68 mounteld on the crushing roller shaft 59b and operably connected to the driving source 31 through a driving chain 69 and a belt 70. The belt 70 interconnects a small pulley wheel 71' mountedY on armature shaft 72 of the motor and a large pulley wheel 73 mounted on a remotely driven shaft 74 which is positioned parallel tcolvthe` armature shaft within the shaft receiving apertures in the vparallel plates 41 and 42. YThe remotely driven shaft is rotatably journalledl within suitable bearing assemblies, not shown in the drawings. One end of the driven shaft extends through the parallel plate 42 and into the driving assembly housing 45 so that the large pulley wheel 73 may be mounted thereon. The driven shaft extends from the housing 45 through the parallel plates 41 and 42 and into the gear train housing 43 where asmall sprocket wheel 75 is mounted ou the end of the shaft. The interconnection of the pulley wheels on the armature shaft and the remotely driven shaft by the belt 70 transmits the rotary movement of the driving source to the driven shaft and to the small sprocket wheel 75'. The driving chain 69 meshes with the sprocket wheel 68 within the gear train housing and with the small sprocket wheel 75 thereby completing the transmission of driving torque from the motor to the crushing mechanism. The rotation of the sprocket 68 by the driving source 31 in the manner just described causes the crushing roller shaft 6 2 to drive each of the intermeshing gears 57, 65a,`65b, 65e, 66a, 66h, 66e, 82a, 82b and 82C of the gear train 44. Therotation of each of the gears inthe gear train induces rotation of the shafts on which the gears are mounted thereby causing the crushing rollers and the feeding rollers to turn in the direction of the arrows shown in Fig. 3. The feeding roller 54 and the crushing rollers f`58a, 58b and 58e are rotated about fixed axes in a clockwise direction as viewed in Fig. 3 whereas the adjustable crushing rollers 76a, 76b, and 76e are rotated in a counterclockwise direction.

In the overall operation of the crushing mechanism, bulk material usually of the type containing granular elements of varying size, is placed in thermaterial storing hopper 34. The granular material in the hopper tiows through the elongated slot 48 in thebottom of theyhopper, along the 'guide Vmembers 49 and over the feeding roller. Energization of thev driving source causes the feeding roller and the crushing rollers to be continuously rotated at constant speed. The material falling onto the feeding roller is fed through the plurality of slots 52a in the material feeding plate 542 and falls onto the fixed roller 58a and the adjustable roller 76a. The rate of ow of material to thecrushing rollers may beregulated to any desiredamountyby exchanging the material feed-r ing feeding platefor onehaving av different number o f slots or for-one having slots of different sizes. The rate of tiow of material to the rollers is preferably adjusted so that granular material will not pile up on the rollers thereby insuring an even ow of material through the Crushers 58a and 76a. The material retaining leaf 51 prevents the granular material from fallingv from the feeding roller and into the crushing chamber 40 without passing through the crushing rollers.

The particles of material are fed through the material feeding plate 52 to the first pair of spaced rollers 58a and 7 6a where all particles of material smaller than the spacing between the rollers are passed therethrough without comminution and all particles larger than the spacing are crushed by the rollers. crushed between the rst pair of rollers are reduced to a size commensurate with the spacing. The output of the first pair of rollers thus comprises a large number of particles of a size corresponding to the spacing between the crushers and a relatively fewer number of particles which are smaller than that spacing. This output is applied to the second pair of rollers 58h and 76b where the crushing operation is repeated by allowing all particles smaller than the spacing between the second pair of rollers to pass unmolested. The spacing between the second pair of rollers is somewhat less than the spacing between the first pair so that the large number of particles which were reduced to a size equal to the spacing between the first pair are again crushed by the second pair of rollers. Most of the particles are reduced by the second pair of rollers to a size identical with the spacing therebetween so that the output of the second pair consists of many particles of material equal in size to the spacing between the second pair of rollers and a smaller number of particles of a size less than that spacing. The crushing operation is repeated in the third pair of rollers 58:.` and 76e in which nearly all of the particles are reduced to a uniform size which is equal to the spacing between the third pair of rollers. Thus each pair of rollers is spaced at a distance corresponding to the size of the particles to be comminuted therebetween in order that the output of the final pair of rollers comprises particles of uniform size. The output of the final pair of rollers flows through the comminuted material delivery passageway 27 and into the detritus receiving chamber 28 in the lower housing.

Some of the granular elements in the storing hopper 34 have been reduced by vibration, jarring and handling to a size which is equal to or somewhat less than the spacing between the final pair of rollers. All of these particles pass directly through the material feeding plate 52, through the spacings between all of the pairs of rollers and into the detritus receiving chamber without comminution. Therefore those particles which equal or are less than the uniform size desired are passed directly to the output of the crusher and are not reduced below this desired size by the crushing mechanism. The particles` of material which are reduced by one of the pairsV of rollers to a size equal to or less than the spacing between the final pair of rollers pass directly to the detritus receiving chamber without further crushing action. In this manner, frictional contact betweenl the particles and the crushing mechanism is minimized and the output in the detritus receiving chamber is free of static charges. The detritus output of the crusher is also free of material lwhich is reduced to dust or powder.

The adjustable bearings 80 permit the spacings be tween the vrollers to be varied in accordance with the material to be crushed or to compensate for changes in spacing due to the wear on the roller surfaces. The output of the crusher which is stored in the detritus receiving chamber 28 may be removed in any convenient manner. As shown in Figs. 1 and 2, the chamber may be provided with an access door 28a through which the output is removed. However, any collecting means well known in the art may be utilized with the crushing mechanism of the present invention. It is obvious that a ma A large number of the particles detritusfgreceiving chamber .may be in legrdraweri from which the material there has been? d escribed an arrangement in which the cruk mgfrollersh ts.79r,79b and `7 9c are adjustable l rel atiivelto,'cooperating crushingaroller shafts 59a, 59h and 59e,respectively.` In /Figss9 to ,12 of the drawings there isillustrate a modicatin of fthelmeans for adjusting the.l osil. l y hafts79,1relativefto,the shafts 9. The corresponding 'partsL ofligs, 9`4 to 12 are designated by the samerefl'ence numerals'. as in the `pt receding embodiments., Asfr'therejllustrated,each `of, `the bearing assemblies 64 is illustrated as being mounted on a flat plate 91, whichin ,a particular embodiment-constructed in accordance. 'with thepresentinvention comprised a square Plate .about 4,'firnsly1es,l squarel Similarly, each of the adjustable bearing assemblies 80,1's lmounted on a, flat plate 90, preferably identical with the at plate 91. With this constructionv therqiseinedtalspace between the corresponding atp vlates,f90 and `91 associated with a pair of crushing `rollers for` accommodating a leaf spring 92 tending tobiasthe bearing` assemblies 64 and 80 apart.

For the purpose of -supporting the'bearing assemblies associated with Vthe atplate 90 forv relative movement witlfrespect-fto -thebearing assemblies 80, or, in other words, for the'purpose Aof providing floating bearings assoeiatedv4 withVVH the adjustable crushing rollers' 76, a slide arrangement foreachr iioatingY bearing'is defined by members 93 and 97 which, areJsuitablyv, secured to the wall 42 bythe fastening means 98. In order properly to adjust the y'bearingfassemblies '80 Vin any desired relationship with respect to the bearingV assemblies 64, suitable adjustable means are associated with the wall 39'comprising a nut member 94 preferably welded to the wall 39 for threadedly receiving an adjustable screw member 96 engageable with the plate 90. A suitable lock nut 95 insures that any adjustment which is made is properly maintained. With the arrangement described it will be apparent that the spring 92 constantly biases the floating bearing against the screw 96, and the space between the crushing rollers may be increased by withdrawing the screw 96, or increasedby the opposite operation of the screw 96 in a manner that will be readily apparent.

For purposes of illustration, the crushing apparatus i of the present invention will now be described in accordance with its embodiment when used for supplying zirconium compound particles for the feeding mechanism disclosed in copending applications Serial Nos. 343,097 and 343,098. As explained in these applications, zirconium is a very hard and brittle material, and when subjected to crushing forces is easily charged by the fric- `tion of the crushing process. The requirements of the feeding system are such that accurate amounts of zir conium compound must be delivered through the feeding mechanism. If the zirconium material accumulates static charges as the compound is crushed, particles of the material tend to adhere to the surfaces of the feeding apparatus and accurate delivery is impossible.

Ordinarily the zirconium compound is purchased in granular bulk form designated as 8 mesh in which each particle is at least 1A; of an inch in diameter. mechanism of the aforementioned applications is designed for use with 40 mesh compound and, therefore, it is necessary to reduce considerably the size of the particles in the 8 mesh compound. The 8 mesh compound is placed in the hopper 34 and flows through the regulating mechanism 33 to the rst pair of rollers 58a and 76a. The slots 52a of the material feeding plate 52 are approximately 1A of an inch wide and %2 of an inch high, so that The feeding Y pass through all of therol1ers, with0ut;= belngkfcruslrcda, hence avoiding `the aforementioned dilcultires vjthwespeet even the lar-gest particles of the 8 mesh material readily Y y ticles in the compound which exceed V32 of an inch in size,

non-friable material, the rollers must bepf sutil whereas, all particles smallerj through the rfrrstrollersjw. ithoun A ond` pair of rollers l5`8b and-,l6b,-.are.space a inch apart in orderto crushall-:particl the iirstpair of rollers which. exceed th ing between the final pair of r j llers is adjust; 0?/ inch t0 Produce, 21,40 mesh-zirconium cpmpoun the particles are of uniform ,sizesv VSin:e-zir :o

ness to withstand considerablewearfin .or q 4 necessityfor frequent replacement. 'lolthis end th ll, ers areA formed ofvanadium tool steel ,which-fis hcz 1se., lrarti @ned te produce azdurable Surfacehavins life. Obviously, the material of r,whichj th Olleltis, Ulf depends upon the friabilityofthematerialtoyberusn All of the particles 4oi:` .,thegranularg,compotlndginfgthet hopper which were originally smaller-tha -V ofzY an, inch to trituration and ,electrostatic charges.M f'Albpartir-lesgbeefr. tween of an inch and;%s ofan inch are-,subjectedonljn to the crushing operation of .thelrollers 5.8c1anclg76,.;ands by this means the 4frictional'forces producingrelectrostatics charges are minimized. Particles, between er-olfraniinchaand /gg of an inch may besubjectednto. only-.oneortwot comminuting actions depending upon thefsize -tozvwhch' particles ,arereduced by the .rst'action :Itis manifesta that the crushing operations towhich each particle-iis sub1-...2. jected are maintained ata minimumfirr:ordentoiredu friction and prevent the formationof .f dust .and'l\other.mi1 nute particles. .l i

From the foregoing explanation 4itis apparentthatttlrenY present invention affords a satisfactory solution to the problem of producing in the output of a crushing apparatus particles of uniform size which are free from dust and powder, and which are not electrostatically charged.

It is to be understood that the foregoing description is pertinent only to a preferred embodiment of the invention to illustrate the principles thereof. Obviously, many modifications and variations of this invention are possible in the light of the above teachings. It is intended by the appended claims to cover all modifications and variations which fall within the true spirit and scope of the present invention.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

l. In a crushing apparatus for producing particles of predetermined uniform size from bulk material having elements of varying size without electrostatically charging the particles produced, the combination of a housing, a container having an opening through which particles of varying size flow, a plurality of aligned cooperating pairs of rollers positioned within the housing and below the opening, each pair of rollers having a spacing therebetween corresponding to the size of particles to be crushed, a distributing roller positioned adjacent the opening in said container for feeding the particles of varying size to a rst pair of the cooperating rollers, a flow regulating plate rigidly mounted upon said housing and having a bottom edge positioned adjacent said distributing roller near the opening, the bottom edge of said plate being provided with a plurality of spaced apertures in order to feed the particles to said rst pair of rollers at a preselected rate, the spacing between said rst pair of rollers being much larger than the predetermined size particles to be produced so that only the largest of the varying size particles are comminuted by the rst pair of rollers whereas all the particles except the large ones pass through the space without comminution successively to the other pairs of rollers, each of the spacings between the pairs of rollers being successively smaller than the spacing between the first pair of rollers so that each pair of rollers comminutes only those particles larger than the spacing therebetween, the last pair of rollers through which the particles pass being spaced apart a distance equal to the predetermined sized particles whereby all the particles below the predetermined size without comminution and all the particles above thelpre'determined size are-reduced to the predetermined size, ndfa collecting means into which all of the particles tlow after passing through the final pair of rollers, the spacing between each of the pairs of rollers permitting the passage of all particles in thecontainer below the predeterminedsizeto pass directly from the container through the Yrollers to the 'collector without comminution.

'2C- The'"combination of claim'l including means for adjusting the spacing between each of the pairs of rollers ,inA order that the` size of the particles owing to the collectingm'eansmay be varied to any desired size.

35A' crushing apparatus asset forth in claim 1 in which thc'spacing between each pair of rollers is adjustable Vby means of floating bearings and spring means effectively-biasing said rollers apart.`

E4Lflnia crushingl apparatus for producing particles vof predetermined uniform size from bulk material having ele'ments'of varying size without electrostatically charging the particles produced, the combination of a housing, a container 4having an opening through which the elements o'fevarying size ow, a plurality of vertically spaced cooperating pairs of rollers positioned within the housing and aligned in pairs below the opening, each pair of rollers having a spacing therebetween corresponding to the sizeof the elements to be crushed therebetween, a collecting means. for receiving the particles after they have passed between all of said pairs of rollers, a distn'buting roller positioned adjacent the opening in said container for, feeding the particles of varying size to a rst pair of the cooperating rollers, a flow regulating plate rigidly mounted upon said housing and having a bottom 12 edge positioned adjacent said distributing roller Ynear the opening in said container, the bottom edge of saidplate being provided with a plurality of Kspaced openings in order to feedthe elements to said rsrt pair of rollers at a preselected rate, the -spacing-betweenv each successive pair ofrollers becoming decreasingly smalleras the ele- Y ments pass from Vone pair of rollers to the next whereby all elements of the material within said container whichV are smaller than the spacing between theiinal pair of rollers pass directly to the collectingv means without being comminuted and all other elements are comminuted only by those pairs of rollers which are spaced apart by a distance less than the size of the elements, thereby to minimize the friction on the comminuted particles and to reduce the electrostatic charges on the particlesrreceived by the collecting means. s Y

5. A crushing mechanism as set forth in rclaim 4 in which the spacing between each of the pairs of rollers is adjustable by means of oating bearings and spring means effectively biasing said rollers apart.

References Cited in the iile o f thispatent UNITED STATES PATENTS4 Y 260,669 Dawson s Julyy 4, 1882A 1,349,221 Nolen Aug. 10, 1920 1,401,445 Rodgers Dec. 27, 1921 1,953,847 Carey c Apr. 3, :1934 2,017,850 Boothman Oct. 22, 1935 2,553,444 Dunn u',May 15, 1951 2,560,837 Alciati July 17, 1951 FOREIGN PATENTS n 482,748 Germany Sept. 19, 1929 

1. IN A CRUSHING APPARATUS FOR PRODUCING PARTICLES OF PREDETERMINED UNIFORM SIZE FROM BULK MATERIAL HAVING ELEMENTS OF VARYING SIZE WITHOUT ELECTROSTATICALLY CHARGING THE PARTICLES PRODUCED, THE COMBINATION OF A HOUSING, A CONTAINER HAVING AN OPENING THROUGH WHICH PARTICLES OF VARYING SIZE FLOW, A PLURALITY OF ALIGNED COOPERATING PAIRS OF ROLLERS POSITIONED WITHIN THE HOUSING AND BELOW THE OPENING, EACH PAIR OF ROLLERS HAVING A SPACING THEREBETWEEN CORRESPONDING TO THE SIZE OF PARTICLES TO BE CRUSHED, A DISTRIBUTING ROLLER POSITIONED ADJACENT THE OPENING IN SAID CONTAINER FOR FEEDING THE PARTICLES OF VARYING SIZE TO A FIRST PAIR OF THE COOPERATING ROLLERS, A FLOW REGULATING PLATE RIGIDLY MOUNTED UPON SAID HOUSING AND HAVING A BOTTOM EDGE POSITIONED ADJACENT SAID DISTRIBUTING ROLLER NEAR THE OPENING, THE BOTTOM EDGE OF SAID PLATES BEING PROVIDED WITH A PLURALITY OF SPACED APERTURES IN ORDER TO FEED THE PARTICLES TO SAID FIRST PAIR OF ROLLERS AT A PRESELECTED RATE, THE SPACING BETWEEN SAID FIRST PAIR OF ROLLERS BEIG MUCH LARGER THAN THE PREDETERMINED SIZE PARTICLES TO BE PRODUCED SO THAT ONLY THE LARGEST OF THE VARYING SIZE PARTICLES ARE COMMINUTED BY THE FIRST PAIR OF ROLLERS WHEREAS ALL THE PARTICLES EXCEPT THE LARGE ONES PASS THROUGH THE SPACE WITHOUT COMMINUTION SUCCESSIVELY TO THE OTHER PAIRS OF ROLLERS, EACH OF THE SPACINGS BETWEEN THE PAIRS OF ROLLERS BEING SUCCESSIVELY SMALLER THAN THE SPACING BETWEEN THE FIRST PAIR OF ROLLERS SO THAT EACH PAIR OF ROLLERS COMMINUTES ONLY THOSE PARTICLES LARGER THAN THE SPACING THEREBETWEEN, THE LAST PAIR OF ROLLERS THROUGH WHICH THE PARTICLES PASS BEING SPACED APART A DISTANCE EQUAL TO THE PREDETERMINED SIZED PARTICLES WHEREBY ALL THE APRTICLES BELOW THE PREDETERMINED SIZE PASS WITHOUT COMMINUTION AND ALL THE PARTICLES ABOVE THE PREDETERMINED SIZE ARE REDUCED TO THE PREDETERMINED SIZE, AND A COLLECTING MEANS INTO WHICH ALL OF THE PARTICLES FLOW AFTER PASSING THROUGH THE FINAL PAIR OF ROLLERS, THE SPACING BETWEEN EACH OF THE PAIRS OF ROLLERS PERMITTING THE PASSAGE OF ALL PARTICLES IN THE CONTAINER BLOW THE PREDETERMINED SIZE TO PASS DIRECTLY FROM THE CONTAINER THROUGH THE ROLLERS TO THE COLLECTOR WITHOUT COMMINUTION. 